37. I remembered (see) him in the meeting ten years ago.

38. Don't forget (turn) off the lights when you leave.

39. I forgot (lock) my door this morning.

40. Thanks very much for (help) me study English.

41. You should give up (smoke). It is bad for your health.

42. He kept me (wait) for a long time.

43. The heavy rain stopped me from (go) out.

44. I often see her (dance) in her room.

45. I heard him (sing) an English song when I was walking past her room.

46. How did Ling Feng make the baby stop (cry) ?

47. When I met Lucy in the street yesterday, I stopped (talk) with him.

48. When the teacher walked into the classroom, the students stopped (talk) . 49. You are very tired, you had better stop (have) a rest.

50. It is not polite (talk) loudly in public.